Projectile with differential tandem shaped charges

ABSTRACT

A projectile utilizing tandem shaped charges is produced, said projectile having superior armor penetration power than previous shape charge projectiles. The invention described herein may be manufactured, used and licensed by or for the Government for govermental purposes without the payment to us of any royalties thereon.

United States Patent 1 [111 3,750,582

Kintish et a1. Aug. 7, 1973 [54] PROJECTILE WITH DIFFERENTIAL 3,416,449 12/1968 Brothers 102/24 HC TANDEM SHAPED CIHIARGIE Inventors: Irving 1L. Kintislh; Irwin Mlarcns,

both of Rockaway, NJ.

The United States of America as represented by the Secretary of the Army, Washington, DC.

Filed: Sept. 3, 1971 Appl. No.: 177,736

Assignee:

US. Cl. 102/56, 102/24 HC Int. Cl. 1 421) 13/10 Field of Search 102/24 HC, 56

References Cited UNITED STATES PATENTS 11/1965 Robinson, Jr. et a1 102/24 HC FOREIGN PATENTS OR APPLICATIONS 341,743 10/1959 Switzerland i. 102/24 HC Primary Examiner-Verlin R. Pendegrass Attorney-I-Iarry M. Saragovitz, Edward J. Kelly etal.

A projectile utilizing tandem shaped charges is produced, said projectile having superior armor penetration power than previous shape charge projectiles.

ABSTRACT The invention described herein may be manufactured, used and licensed by or for the Government for govermental purposes without the payment to us of any royalties thereon.

4 Claims, 2 Drawing Figures PAH-INTEL] AUG 'IISH 3 75Q,582

FIG. I

INVENTORS IRVING L. KINTISH BY IRWIN MARCUS Z/u/V? 711.- I away-W1 Mal/M wfywm m PROJECTIILE WlITlil DIFFERENTIIAL TANDEM SHAPED ClliiAlltGllEfi DESCRIPTION OF THE INVENTlON In the projectile explosive art it has been found that the armor piercing ability of a given quantity of explosive charge may be optimized by forming the forward portion of the charge with an appropriate configura' tion. Such charges are generally referred to as shaped charges, and their armor piercing effectiveness results from providing that shape in the front of the charge which affords the greatest directivity and concentration ofexplosive force in a localized area. A particularly effective configuration for such shaped charges is that obtained by forming a conical cavity or recess in the forward end of the charge and lining the cavity with some material e.g. copper.

When the end of the explosive charge opposite the liner is initiated, the detonation wave passes over the metal liner causing the liner to collapse upon itself. When the collapsing liner material reaches the axis of the system, it divides into two parts. A small part forms an extremely high-velocity jet and the other part forms a slower but more massive slug.

The high velocity jet is responsible for the relatively deep penetration achieved by the shaped charge. The tip of the jet attains a velocity of about 25,000 feet/sec. and the rear portions of the jet attain velocities of nearly 5,000 feet/sec. This velocity difference within the jet is a result of the physical characteristics of most shaped charges. At the apex of the cone, the ratio of the explosive charge to the liner mass is relatively large. However, as the detonation progresses down the liner, the mass of the liner increases while the amount of ex-- plosive available to move it decreases. The ratio goes to zero at the base of the liner because there is no explosive at the base. Therefore, the various portions of the liner reach the axis at progressively lower velocities and generate a jet having a velocity gradient along its length.

Because the jet impacts a target at such high velocities, an exceedingly high pressure is generated. Typically, this pressure is about 4 X psi. The high pressure causes both the jet and the target to deform hydrodynamically. The jet moves the target material radially and flows with it. Penetration continues in this manner until the jet is used up or until the jet decreases to some critical value. Until our invention, penetration of armor by a high velocity jet was limited by the above mentioned forces to approximately 10-12 inches.

An important object of this invention is to increase the efficiency of shape charge projectiles by introducing a follow-through charge in the jet hole formed by the initial charge.

A further object of this invention is to increase the area of damage in a target by introducing a secondary explosive force through a jet hole made by the initial shape charge in the projectile.

Many other objects and many of the attendant advantages of this invention will be readily appreciated as the same become better understood by reference to the following detailed description.

The present invention involves the use of two shape charges in one projectile. The first shape charge upon initiation will form the aforementioned jet which proceeds through a small central hole in a perforated disc, said disc separating the two charges. The slower and later formed slug of the initial change will be impeded by the separating disc causing formation of a shock wave sufficient to detonate the second shape charge. The second shape charge is chosen from explosives having explosive velocities greater than those of the first shape charge such that the jet created by the second charge will precede the slower slug of the first charge and enhance the penetration caused by the jet of the first charge.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a sectional view of such a tandem shape charge system.

FIG. 2 presents a frontal view of the perforated disc used to separate the charges.

DETAILED DESCRIPTION OF THE INVENTION Referring now more particularly to the drawings, a projectile container 1 is shown in FIG. 1 and therein an initial shape charge 6 having a conical liner 7'. The projectile container may be made ofa low carbon steel or other fragmentation metals. The shape charge 6 is preferably conical in shape although it may also be fluted. The metallic linerfor the above shape charge may be any material designed to increase the depth of shape charge penetration e.g. copper, aluminum, antimony or alloys of the above and the liner configuration is chosen to conform to the particular shape charge used. A conical shape charge and liner with an angle of 42 is preferable.

The explosive for the shape charge may be any noninitiating high explosive known to the art such as ali' phatic, aromatic and heterocyclic nitrates, nitrocompounds and nitramines, binary explosives (mixtures of 2&6 trinitrotoluene and a second explosive such as cyclotrimethylene trinitramine), and plastisol explosives such as PBX percent cyclotrimethylene trinitramine, 8.5 percent polystyrene and 1.5 percent dioctylphthelate).

The disc 4 may be made of reinforced fiberglass or various metals such as steel, copper and alloys thereof. The disc is approximately 1/8 1/4 inches thick and is perforated as shown in FIG. 2. The free space 8 or aperture in the center of the disc is so calculated in size as to allow the jet, formed by the initial shape charge detonation, to pass through unhampered while retarding any slug formed by the initial shape charge and liner particles.

The initial shape charger 6 is positioned in the projectile such that the distance between 4 and 5 shown in FIG. 11 is about 1-1 1/2 cone diameters. This distance provides a sufficient stand-off between the initial shape charge and the projectile nose such that optimum effectiveness can be attained from the initial shape charge detonation.

Initiation of shape charge 6 is accomplished by initial detonating agents such as lead azide, mercury fulmimate and diazodinitrophenol. These detonating agents are in turn initiated by piezoelectric or base fuzing techniques known to the art.

The secondary shape charge 3 and shape charge liner 7 may be conical, fluted or hemispherical (as shown in FIG. 1) in configuration. As in the initial shape charge system the liner material may be copper, aluminum, antimony, or alloys thereof. The shape charge explosive as in the initial shape charge may be an aliphatic, aromatic or heterocyclic nitrate, nitro compound, or nitra- 3 mine, a binary explosive, or a plastic explosive provided that the explosive chosen must have a greater detonation rate than the explosive chosen for the initial charge and secondly that the explosive is susceptible to shock wave detonation.

The standoff distance between the secondary shape charge and the projectile nose is about 34 cone diameters. This distance will allow sufficient time for initiation and jet formation of the secondary charge. Initiation of the secondary charge is accomplished by the shock wave formed when the slug from the initial shape charge impacts with the disc which divides the two charges. The perforations in the disc as shown in FIG. 2 allow for extrusion of the slug such that a near planar shock wave is produced which will not cause excessive breakup of the secondary charge while initiating it.

The second charge when detonated will form a jet that will penetrate and enhance the perforation of the target already accomplished by the jet of the initial charge.

Thusly through the practice of our invention a projectile is produced which has greater perforation power and which is more efficient than previous shape charge projectiles.

We wish it to be understood that we do not desire to be limited to the exact detail of construction shown and described for obvious modification will occur to a person skilled in the art.

We claim:

1. A projectile comprising:

a hollow shell having longitudinally disposed therein a pair of spaced apart shaped charges each provided with an abutting forward liner and having a rearwardly convergent configuration, wherein the forward shaped charge possesses a greater explosion velocity than the rear shaped charge and is susceptible to shock wave detonation from the rear shaped charge,

means for initiating the rear shaped charge explosive,

a disc adjacent the rear end of the forward charge having a central aperture which is smaller than the slug from the rear charge, said forward charge and liner being provided with coaxial openings therethrough which are aligned with said aperture,

whereby when the rear charge is detonated and a jet and slug are formed therefrom, the central aperture and openings allow passage of the jet while the disc retards passage of the slug and thereby imparts a shock wave which detonates the forward shape charge.

2. The projectile of claim 1 wherein the distance between the disc and the liner of the rear charge is between 1 and 1.5 shape charge diameters, I

3. The projectile of claim 1 wherein the 'disc is a material selected from the group consisting of steel, copper, alloys of steel, alloys of copper and reinforced fiberglass.

4. The projectile of claim 1, wherein the disc is provided with a plurality of openings therethrough in addition to said central aperture. 

1. A projectile comprising: a hollow shell having longitudinally disposed therein a pair of spaced apart shaped charges each provided with an abutting forward liner and having a rearwardly convergent configuration, wherein the forward shaped charge possesses a greater explosion velocity than the rear shaped charge and is susceptible to shock wave detonation from the rear shaped charge, means for initiating the rear shaped charge explosive, a disc adjacent the rear end of the forward charge having a central aperture which is smaller than the slug from the rear charge, said forward charge and liner being provided with coaxial openings therethrough which are aligned with said aperture, whereby when the rear charge is detonated and a jet and slug are formed therefrom, the central aperture and openings allow passage of the jet while the disc retards passage of the slug and thereby imparts a shock wave which detonates the forward shape charge.
 2. The projectile of claim 1 wherein the distance between the disc and the liner of the rear charge is between 1 and 1.5 shape charge diameters.
 3. The projectile of claim 1 wherein the disc is a material selected from the group consisting of steel, copper, alloys of steel, alloys of copper and reinforced fiberglass.
 4. The projectile of claim 1, wherein the disc is provided with a plurality of openings therethrough in addition to said central aperture. 